Textile process and composition



United States Patent TEXTILE PROCESS AND COMPOSITION Fred V. Coglianese, Dover, N.J., and Bryce E. Tate,

Niantic, Conn., assignors to Chas. Pfizer & Co.,

Inc, New York, N.Y., a corporation of Delaware N 0 Drawing. Continuation-impart of application Ser. No. 370,058, May 25, 1964. This application Apr. 22, 1965, Ser. No. 450,138

5 Claims. (Cl. 117-138.8)

ABSTRACT OF THE DISCLOSURE Polymeric material prepared by polymerizing itaconic acid with acrylic acid in a weight ratio of from about 0.5: 1.0 to about 2.0: 1.0 and having a Brookfield viscosity of from about 500 cps. to about 50,000 cps. in a 33% aqueous solution at 25 C. employed as a sizing agent for polyolefin yarn.

Cross reference to related application This application is a continuation-in-part of application Ser. No. 370,058 as filed May 25, 1964, and now abandoned.

This invention relates to an improved textile process and to the compositions produced thereby. More particularly, it is concerned with a new and improved method for sizing synthetic textile yarn, especially polyolefin yarn, and with the novel compositions produced by this treatment.

In the past, various chemical agents have been used in the textile industry to size textile yarn including the more recently developed synthetic textile fibers such as nylon, Dacron, Orlon and the like, i.e., fibers derived from the polyamides, polyethylene terephthalate, polyacrylonitrile, etc. However, no one has as yet reported a satisfactory method for sizing polyolefin yarn such as polyethylene, polypropylene, etc. A primary object of the present invention, therefore, is to provide a solution to this problem since this will obviously be of great importance to the industry in general, as well as to the users of this yarn in particular. Other objects and advantages of the present invention will become obvious to those skilled in the art from the description which follows.

In accordance with the present invention, it has now been found possible to solve this problem of the prior art by applying to the polyolefin yarn as sizing agent therefor a polymeric material prepared by polymerizing itaconic acid with acrylic acid in a weight ratio of from about 0.5 :l.0 to about 20:10, respectively, whereby a copolymer is formed having a Brookfield viscosity reading in the Still-50,000 centipoise range when measured in a 33% aqeuous solution at 25 C. That these findings are truly surprising can be attested to by the fact that both polyitaconic acid itself and polyacrylic acid fail to give satisfactory results when tested under the same conditions, despite their similarity in structure to the instant copolymer and despite the fact that polyacrylic acid is a good sizing agent for nylon and other synthetic yarns which are not polyolefins. As a matter of fact, other copolymers of itaconic acid with acrylic acid which lie outside the scope of the aforestated viscosity range are also equally ineffective in this respect when considered from a practical point of view. For instance, below a Brookfield viscosity reading of 500 cps. in 33% aqueous solution, the polymer does not have sufiicient tenacity to protect the yarn, while above the 50,000 cps. mark some difiiculty is encountered in scouring off the size.

On the other hand, the advantages offered by the use of the new polymeric sizing agents of this particular invention are truly manifest, since they now provide for the first time a new polyolefin warp size in addition to being useful as excellent sizing agents for nylon as well. As sizing agents, they give good adhesion properties and hence, little shed, good protection during weaving, no gumming on the machine, stability in the size bath, and easy scourability as previously mentioned. Furthermore, they are also relatively easy to prepare and simple to handle in their operation and for this reason, they also find themselves to be economically attractive to the general user in this field.

In accordance with the process of the present invention for making the polyolefin size, the two co-monomers of choice, viz., itaconic acid and acrylic acid, are heated together in the aforestated desired weight ratios in an aqueous solvent medium in the presence of a free-radical initiator at a temperature that is in the range of from between about 35 C. and C., until such time as said copolymerization reaction is substantially complete with respect to the formation of said polymer, i.e., until a copolymer product is achieved having a Brookfield viscosity of from about 500 cps. to about 50,000 cps. in 33% aqueous solution at room temperature. Usually, this requires a time period of several hours, but will vary depending upon the catalyst, temperature and other reaction conditions employed. A preferred temperature range would be about 40-70 C. Normally, the course of the reaction is followed by means of such standard techniques as bromine number analysis and the like, which measure the amount of unsaturated monomer remaining in the mixture at any given time. Suitable free-radical initiators for use in this reaction include potassium persulfate, ammonium persulfate, benzoyl peroxide, azobisisobutyronitrile, etc., or a redox system comprising persulfate-metabisulfite, with the more water-soluble agents being preferred. All these freeradical initiators are generally used at concentration levels ranging as low as from about 0.15 up to about 2.0 mole percent, based on the total weight of the comonomers employed. The concentration of the latter two ingredients in solution is generally not critical, but it is preferred in practice to keep the combined itaconic-acrylic acid weight concentration in the 10-50% concentration range for the sake of convenience and economy.

Upon completion of the polymerization reaction, the desired copolymer may be recovered in solid form from the aqueous solution by means of precipitation therefrom with a non-solvent such as acetone, for example. This step is then followed by filtration or decantation to remove the aqueous liquid from the polymer, which can then be subsequently dried to constant weight and further purified, if necessary, by additional treatment with aque' ous acetone in the usual manner. This material is then used to prepare the sizing solution, wherein the copolymer is dissolved in water to provide a copolymer solution strength of from about 1% up to about 20% by weight. Alternatively, one may also simply dilute the original copolymer reaction solution obtained after completion of the copolymerization step to a value in the aforestated concentration range by merely adding a sufficient amount of water thereto without prior isolation of the polymer and still achieve highly satisfactory results in the sizing tests. a

In either case, the solution thus obtained is then used to size the polyolefin yarn or fiber by merely treating the latter material with said aqueous solution in the usual manner in accordance with the standard practice of the textile industry. This usually requires that the size bath temperature be slightly warm to hot, so that a temperature that is in the range of from 35 C. up to about 75 C. is generally most satisfactory for these purposes. In general, the polyolefin yarn must be sized with at least about one part by weight, per parts by weight of the yarn,

of the polymeric sizing agent of this invention in order for completely effective and highly satisfactory results to be achieved. However, the latter value is not absolutely critical since some sizing effect is alway obtained below the lower limit hereinbefore stated. The important point to remember, however, is that the polymeric sizing agent must always be one chosen from the group consisting of those copolymers which are prepared by polymerizing itaconic with acrylic acid in a weight ratio of from about 0.5 :1.0 to about 2.0210, respectively, as previously discussed, whereby a copolymer is produced having a Brookfield viscosity reading of from about 500 cps. to about 50,000 cps. when in 33% aqueous solution at 25 C.

To further illustrate this point, we wish to emphasize the copolyrner formed by polymerizing itaconic acid with acrylic acid in a l.8:l.0 reaction weight ratio, respective ly, i.e., in equimolar amounts. This particular copolyrner, which has a Brookfield viscosity reading in the neighborhood of 9S03,200 cps., has been found to be a most highly excellent polypropylene warp size on testing and is therefore, one of the most preferred member species of this invention for these particular purposes, as is also the copolymer of 1.0:l.0 reactant weight ratio. While the other copolymers of this invention work also equally as well, those remaining outside the scope of the aforestated viscosity range are just not at all effective from a practical standpoint when considered as sizing agents for the polyolefin yarns.

This invention is further illustrated by the following examples, which are not to be construed in any way or manner as imposing limitations upon the scope thereof. On the contrary, it is to be clearly understood that resort may be had to various other embodiments, modifications and equivalents thereof which readily suggest themselves to those skilled in the art without departing from the spirit of the present invention and/ or the scope of the appended claims.

EXAMPLE I In a four-necked, -liter round-bottomed flask equipped with reflux condenser, thermometer, mechanical stirrer and nitrogen-inlet tube, there is placed 910 g. (7.0 moles) of refined itaconic acid in 2828 ml. of de-ionized water. The stirrer is then started and heat is applied by means of an oil bath, while 504 g. (7.0 moles) of acrylic acid is added to the mixture. The internal temperature is next brought to a value in the neighborhood of 50i2 C., while a flow stream of nitrogen gas is slowly introduced into the heated system. Upon equilibration, 18.92 g. (0.07 mole) of potassium persulfate is added and the reaction is thereafter followed by means of bromine number analysis. At the end of 31 hours and 15 minutes, an additional amount (9.46 g., 0.035 mole) of potassium persulfate is added. The reaction is then continued until a total time of 49 hours and 15 minutes has elapsed from the starting point (bromine number analysis at the 46 hour and 35 minute mark showed a 97% completeness of reaction). The itaconic acid-acrylic acid copolymer so produced possesses the following characteristic physical properties in aqueous solution: Brookfield viscosity, #2 spindle, 30 rpm. at 25 C., 970 centipoise (cps.); specific (gfgiglity at 15/15 C., C., 1.154; n /C g, 0.64; n /C g,

The solid polymer is then recovered from the aqueous solution by carefully pouring the latter into 15 times its volume of acetone, whereby the polymer slowly precipitates therefrom in the form of a gummy solid. After removal of the acetone liquid phase by decantation, the polymer is redissolved in water and reprecipitated again from acetone to obtain a white powder, which is then subsequently collected on a filter funnel by means of suction filtration and dried thereon to constant weight while under diminished pressure to afiord the pure product, viz., the itaconic-acrylic acid copolymer of 1.8210 reactant weight ratio.

EXAMPLE H The procedure described in Example I is then repeated to prepare other itaconic-acrylic acid copolymers in the reactant Weight ratio range of 1.6210 to 2021.0, respectively, by merely increasing or decreasing the amount of itaconic acid in each run as the case may be. For instance, 1008 g. of itaconic acid is used instead of 910 g. to prepare the 2.0: 1.0 reaction weight ratio copolyrner, whereas only 806.4 g. of the same said acid need be used to react with 504 g. of acrylic acid to prepare the 1.6:1.0 reactant weight ratio copolyrner. Under these circumstances, slightly different copolymers are obtained in each case, i.e., their viscosities differ, with the copolymer of 1.6:1.0 reactant weight ratio having the higher viscosity reading but still being within the aforestated Brookfield viscosity range. These copolymers are then tested as will hereinafter be described in the examples to follow.

EXAMPLE III A polypropylene multifilament yarn of 210 denier, having 8 twists/inch, was threaded on a Calloway laboratory slasher machine, while a 7% aqueous solution of the itaconic-acrylic copolyrner prepared as described in Example I, viz., the copolyrner obtained by reacting itaconic acid with acrylic acid in a 1.8: 1.0 weight ratio, respectively (i.e., on an equimolar basis), was introduced into the size box of said slasher machine. The sizing was then conducted at a bath temperature of 120 F. (43-49" C.), and the squeeze rolls were adjusted to give a size add-on of 2.0%. The so-treated yarn was then subsequently tested on a Duplan testing machine to determine the abrasion resistance thus produced. It was found that adhesion of the size to the fiber was excellent and that a Duplan test result of cycles was obtained before all the filament ends became loose. This value Was far superior to that obtained with unsized polypropylene (the control), where only a 10-cycle reading could be obtained. Further, the size on the yarn was easily removed by means of standard scouring treatments applied thereafter.

EXAMPLE IV The sized polypropylene prepared as described in the above manner (where itaconic-acrylic acid copolymer of 1.8:1.0 reactant weight ratio is the sizing agent) was subjected to a warp shed test and compared at the same time in this respect with the polyethylene glycol type resins used in the trade for sizing polypropylene filter cloth. It was found that polypropylene yarn sized with the itaconicacrylic acid copolyrner at an add-on level of 2.03% gave a zero reading, i.e., no breaks, in the warp shed tests at 40 yards/fiber in comparison with a similar performance by the yarns sized with the aforementioned polyethylene oxide derivative at an add-on level of 10.5%. The shed which formed in the present instance was powdery, not gummy and was easily blown off the machine.

EXAMPLE V The procedure described in Example I is essentially followed on a larger scale except that 24.61 kg. of itaconic acid and 13.61 kg. of acrylic acid in 67.6 liters of deionized water are the reactants employed. This mixture is next heated to 48 C., at which point 514 g. of potassium persulfate in 8,875 ml. of water is added. The temperature is then adjusted to 50:1" C. and thereafter maintained at this point for 34 hours, with an additional amount (250 g.) of potassium persulfate having been added at the 20- hour mark. A bromine number analysis at the 27-hour mark indicated a 96% completeness of reaction. The itaconic-acrylic acid (1.8:1.0 reactant weight ratio) copolymer so obtained possesses the following characteristic physical properties: Brookfield viscosity, #2 spindle, 30 rpm. at 27 C., 3,170 centipoise;

EXAMPLE VI A 3-twist/inch multifilament polypropylene yarn was sized in the manner of Example 111 except that the copolymer employed was that of Example V and the add-on level of said copolymer was now by weight of the fiber instead of the lower level previously used. Weaving tests performed on the treated material showed a 100% efficiency, i.e., no breaks, even after three days of weaving and this, despite the fact that no surfactant was required to obtain such highly satisfactory results. Although some shed was noticed on the reeds in the loom, this was not considered serious since it was not excessive and since it was a dry powder which could easily be blown off.

EXAMPLE VII The testing procedures described in the preceding examples with respect to polypropylene yarn (Examples III-IV) are repeated with polyethylene yarn and comparable results are obtained in each case. In like manner;

Polyolefin Yarn Copolymer Reactant,

Wgt. Ratio Polyethylene Itaconic-acrylic 1. 6:1 0 Polypropylene do 1.6:1 0 Polyethylene do 1.8:1 0 Polypropylene -do 2. 0:1 0 Polyethylem rln 2. 0:1 0

EXAMPLE VIII In a 200-gallon stainless-steel stirred reactor vessel equipped with a water jacket for cooling and heating purposes as well as with an automatic stirrer, there is placed 176.8 lbs. of refined itaconic acid in 625.68 lbs. of deionized water. The stirrer is then started and the system is purged with nitrogen by displacing the air above the solution with said gas. The purged bath is then heated to 45 C., at which point 176.8 lbs. of glacial acrylic acid is added to the system. The temperature is next raised to 47 C. in order to facilitate homogeneity of the batch and then brought back to 42 C., at which point the catalyst is added, i.e., 1165 g. of potassium persulfate dissolved in 82.5 lbs. of water. The reaction is thereafter followed by bromine number analysis, while maintaining the temperature of the system in the neighborhood of 50i2 after first standing at 41.5 C. for 35 minutes. At the end of approximately 22 hours reaction time, bromine number analysis showed the reaction, i.e., the copolymerization, to be 98.5% complete. The aqueous solution containing 33.4% by weight of the copolymer so produced is then drained from the reactor vessel and stored in amber-glass sample bottles and polyethylene-lined drums (total weight of solution, 1060.19 lbs.). This particular itaconic acid-acrylic acid copolymer of 1:1 reactant weight ratio is found to possess the following characteristic properties in said 33.4% aqueous solution: Brookfield viscosity, #4 spindle, 30 r.p.m. at 25 C., 12,200 cps.; specific gravity at /15 C., 1. 88; n, 1.3904.

The above copolymer solution of 33.4% total solids concentration strength is then filtered through a large Buchner funnel dressed with polypropylene cloth to remove dust particles and impurities, and the resulting aqueous filtrate is then subsequently diluted with sufiicient deionized water to afford a solution of 25.5 total solids copolymer concentration strength. This is done by simply charging 898 lbs. of the aqueous filtrate of 33.4% concentration strength with 278 lbs. of the de-ionized water with the aid of constant stirring. The resulting batch is next heated to 35 C. and stirred at that point for four hours. After cooling to room temperature under a nitrogen atmosphere, it is subsequently filtered and the filtrate collected, i.e., packaged, in the same manner as before in the case of the 33.4% solution (total weight of 25.5% solution, 1084.4 lbs.). The copolymer is found to possess the following characteristic properties in this 25 .5 aqueous solution: Brookfield viscosity, #3 spindle, 30 rpm. at 25 C., 1570 cps; specific gravity at 15 15 C., 1.1190; n 1.3736.

The actual copolymer is isolated in the same manner as that described in Example I for the 1.8:1.0 reactant weight ratio polymer, whereby acetone is employed as the anti-solvent of choice to precipitate the desired copolymer from aqueous solution. In this way, the pure itaconicacrylic acid copolymer of 1.0:1.0 reactant weight ratio is obtained in the form of a white powder.

EXAMPLE IX In a 10-ga1lon stainless-steel stirred reactor vessel of the type employed in Example VIII, there is placed 5.6 lbs. of itaconic acid and 11.2 lbs. of glacial acrylic acid in 50.7 lbs. of water. The air above this solution is then displaced with nitrogen and the temperature is raised to 60 C. At this point, 61 g. of potassium persulfate is added as catalyst and the reaction temperature is maintained at 60 C. with appropriate heating and cooling until bromine number analysis of the product shows polymerization to be essentially complete (this step is achieved in approximately 15-20 hours). The aqueous solution containing 25% by weight of the copolymer is drained from the reactor vessel and stored in polyethylene-lined drums. Isolation of the solid copolymer of 0.5:1.0 itaconic-acrylic acid reactant weight ratio is then achieved in the same manner as that described in Example I for the 1.8: 1.0 copolymer.

EXAMPLE X A warp was made with spun polypropylene 13/1 yarn (i.e., a yarn having 13 hanks per pound, which is also a single and not a Z-ply yarn). The warp was of standard construction, having 63 ends and 35 picks 'per inch, and being 12 inches wide and 64 yarns long. This particular warp was slashed in the following manner, viz., by mixing 6.5 lbs. of potato starch and 6.25 lbs. of itaconic acidacrylic acid copolymer of 1.0210 reactant weight ratio (in the form of the 25.5 aqueous solution prepared in Example VHI) together in the cold, then diluting the mix to five gallons with water, heating to F. (71 C.) and holding (cooking) at that point for 30 minutes. The running conditions were as follows: size box, 160 F.; can temperature, radiant 20%, F., 200 F., 190 F. and 200 F., at approximately 8 yards per minute. At the end of the run, it was found that the treated warp performed well and was highly satisfactory as to weavability. As a matter of fact, a higher quality woven product was actually produced and there was no sticking or gumming left on the loom.

EXAMPLE XI The procedure described in Example X to size spun polypropylene yarn, using the itaconic-acrylic acid copolymer of 1.0:1.0 reactant weight ratio prepared in Example VIII, is repeated here with polyethylene spun yarn instead and equally satisfactory results are obtained.

EXAMPLE XII The procedure described in the preceding two examples is repeated to size polyethylene and polypropylene spun yarn, but using the itaconic-acrylic acid copolymer of 05:10 reactant weight ratio, as prepared in IX, instead as the sizing agent of choice. In each of these two cases,

the results obtained are comparable to those reported previously in the aforementioned examples.

What is claimed is:

1. A polyolefin yarn sized with at least about one part by Weight, per 100 parts by weight of the yarn, of a copolymer of itaconic acid and acrylic acid in a weight ratio of from about 0.5 21.0 to about 2.0:1.0, said copolymer having a Brookfield viscosity of from about 500 cps. to about 50,000 cps. in a 33% aqueous solution at 25 C.

2. The polyolefin yarn as claimed in claim 1 wherein the polyolefin yarn is polypropylene sized with a copolymer of itaconic acid and acrylic acid prepared by polymerizing the latter two compounds together in an approximate Weight ratio of from about 0.5 21.0 to about 2.0:1.0, respectively.

3. The polyolefin yarn as claimed in claim 1 wherein the polyolefin yarn is polyethylene sized with a copolymer of itaconic acid and acrylic acid prepared by polymerizing the latter two compounds together in an approximate weight ratio of from about 0.5:1.0 to about 2.0:1.0, respectively.

4. The polyolefin yarn as claimed in claim 1 wherein the polyolefin yarn is polypropylene sized with a co- References Cited UNITED STATES PATENTS 2,789,099 4/1957 Rife et al 26029.6 3,055,873 9/1962 Hull et al 26078.8 3,228,791 1/1966 Armour et a1. 1l7138.8 3,236,685 2/1966 Caldwell et al 1l7138.8

OTHER REFERENCES Journal of Organic Chemistry, vol. 24, pp. 599-605 (1959), QD241J6.

WILLIAM D. MARTIN, Primary Examiner.

T. G. DAVIS, Assistant Examiner. 

